1. Technical Field
The present invention relates to a liquid jetting head and a method for manufacturing the same.
2. Related Art
At present, ink jet methods have been put in practical use as high definition, high-speed printing methods. A device that discharges ink droplets is called an ink jet head, which is an important member in the ink jet method and is being actively studied. Among the methods for jetting ink droplets, a method in which an ink jet head is provided with a piezoelectric is one of the most useful methods. In an inkjet head, a piezoelectric may be interposed between electrodes, thereby forming a capacitor structure. As a typical piezoelectric material, lead zirconate titanate (PZT) (Pb(Zr1-xTix) that is a perovskite type oxide may be enumerated.
It is necessary to suppress leakage current as much as possible in order for an ink jet head to maintain its mechanical reliability. One of the major causes that increase the leakage current is moisture in the atmosphere that adheres to side surfaces of the capacitor structure. Adhesion of moisture in the atmosphere to the side surfaces of the capacitor structure may cause a problem in that leakage current may be generated across electrodes at both ends of the capacitor through the side surfaces, which may eventually lead to dielectric breakdown.
A variety of measures has been developed for suppressing leakage current. For example, Japanese Laid-open Patent Application JP-A-2001-138511 proposes an ink jet recording head in which a lid-like cover is formed with a thin film that does not directly contact its capacitor structure, and dry fluid of inert gas is contained in the cover, whereby the air atmosphere does not contact the piezoelectric. However, the ink jet recording head described in Japanese Laid-open Patent Application JP-A-2001-138511 still entails problems in its method for solution and manufacturing method. In the method described in the document, resist films are removed by a wet process, such that contact with the atmosphere cannot be avoided. Furthermore, the document describes that holes are opened in the lid-like cover that covers the capacitor structure, etching is conducted using the holes, and then the holes are again filled with adhesive. However, such a process requires positional accuracy, and may not necessarily be an easy manufacturing method.